📊 Standard Deviation & Variance Calculator
Calculate sample and population standard deviation (s and σ), variance, mean, sum of squares, and statistical data spread. 100% free.
Free No Signup Required Browser-Based
Sample Standard Deviation (s)
5.2372
Mean (μ): 18.0000 (Based on 8 data values)
Population SD (σ)
4.8990Sample Variance (s²)
27.4286Population Variance (σ²)
24.0000Median & Range
18.50 (Range: 13)How to Use Standard Deviation & Variance Calculator
- Enter comma- or space-separated numbers into the data input box
- Select sample data presets to test common statistical models
- Review sample SD, population SD, variance, and median spread
📖 Technical Encyclopedia & Standards Reference
Calculate sample and population standard deviation (s and σ), variance, mean, sum of squares, and statistical data spread. 100% free. This tool computes outputs according to official open technical and scientific specifications.
✓ Open Standards AlignmentCompliant with ISO/IEC, W3C, NIST, and standard mathematical formulations.
✓ 100% Client-Side / SecureZero server logging. Computations execute entirely in your local browser sandbox.
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Frequently Asked Questions
What is the difference between Sample and Population standard deviation?
Population Standard Deviation (σ) divides by N when the complete dataset is known, while Sample Standard Deviation (s) uses Bessel’s correction dividing by (n - 1) to provide an unbiased estimate for a sample.
What does standard deviation measure?
It measures the dispersion or spread of values around the arithmetic mean. A low standard deviation indicates data points clustered tightly near the mean.